KR100364227B1 - Epoxy resin composition for sealing of semiconductor device - Google Patents

Abstract

The present invention relates to an epoxy resin composition for sealing semiconductor elements using a mixture of an ortho novolak epoxy resin and a bifunctional epoxy resin having a naphthalene structure in a weight ratio of 2: 8 to 6: 4. Introducing a suitable mixture of low viscosity epoxy resin and ortho cresol novolak epoxy resin with structure improves curing characteristics, and high filling inorganic filler reduces moisture absorption and thermal expansion coefficient and improves mechanical strength It is to provide an epoxy resin composition for forming a semiconductor device excellent in molding characteristics and reliability by suppressing the generation of voids generated during device molding.

Description

Epoxy Resin Compositions for Semiconductor Device Sealing

The present invention relates to an epoxy resin composition, and more particularly, an epoxy mixture made of an ortho cresol Novolac epoxy resin and a bifunctional epoxy resin having a naphthalene structure, and a phenol. The present invention relates to an epoxy resin composition for sealing semiconductor devices having excellent high temperature crack resistance, curing properties, mechanical properties, and excellent reliability and molding properties including novolak-based curing agents, curing accelerators, modified silicone oils, and inorganic fillers.

In recent years, the degree of integration of semiconductor devices has been improved day by day, resulting in finer wiring, larger device size, and rapid development of multilayer wiring, and in the case of a package that protects the semiconductor devices from the external environment, the density of the printed circuit board is high. In terms of mounting, that is, surface mounting, compactness and thinning are accelerating.

As described above, in a resin-sealed semiconductor device in which a large semiconductor device is sealed in a small and thin package, the frequency of failure such as package crack or corrosion of an aluminum pad may increase due to thermal stress caused by changes in temperature and humidity of the external environment. .

Therefore, the high reliability of the sealing epoxy resin molding material is so strong that the method of lowering the modulus of elasticity for low stress, the method of lowering the coefficient of thermal expansion or the use of a high-purity curing agent, the reduction of impurities by applying the ion trapper and There is a method of high filling the inorganic filler to reduce the moisture absorption.

As a method of lowering the modulus of elasticity, an epoxy resin molding material in which Japanese polymers No. 63-1894 and Japanese Patent Laid-Open Nos. Hei 5-291436 are blended and modified with a silicone polymer having excellent thermal stability using various rubber components has been proposed. Since there is no compatibility with the epoxy resin and hardening | curing agent which are base resins of this molding material, microparticles | fine-particles are disperse | distributed in a base resin, and the low elastic modulus which maintains heat resistance can be achieved. In addition, for low thermal expansion, a method of increasing the filling amount of an inorganic filler having a low coefficient of thermal expansion is preferable.However, the low flowability and high elasticity of the epoxy resin molding material are increased due to the increase of the filling amount of the inorganic filler. 11355 introduces a technique for the formulation of large amounts of spherical fillers by controlling their particle size distribution and particle size.

The present invention introduces a mixture of a low viscosity epoxy resin having an naphthalene structure and an ortho novolak-based epoxy resin, and has excellent curing properties.As a high filling inorganic filler, moisture absorption and thermal expansion coefficient are reduced and mechanical strength is improved. At the same time, by suppressing the generation of void (Void) generated during the semiconductor device molding to provide an epoxy resin composition for forming a semiconductor device excellent in molding characteristics and reliability.

The present invention is an epoxy resin composition comprising an epoxy resin, a curing agent, a curing accelerator, a modified silicone oil and an inorganic filler as essential components, wherein the epoxy resin is represented by the following formula (1) and formula (2), the weight ratio of 2: 8 to 6: It is related with the epoxy resin composition for semiconductor element sealing characterized by the above-mentioned.

That is, the present invention is an epoxy resin mixture obtained by mixing an ortho novolak epoxy resin represented by Formula 1 below and a bifunctional epoxy resin having a naphthalene structure represented by Formula 2 at a weight ratio of 2: 8 to 6: 4. and

A hardening agent, a hardening accelerator, a modified silicone oil, and an inorganic filler are essential components, and the inorganic filler is contained in an amount of 82 wt% or more based on the total composition.

Hereinafter, the present invention will be described in detail.

In the epoxy resin used in the present invention, it is preferable that the epoxy resins represented by the formulas (1) and (2) have a weight ratio of 2: 8 to 6: 4, and if the weight ratio is less than 2: 8, for example, 0:10, etc. In the case, the curing property is lowered, so that the occurrence of molding failure is high, and in the case of larger than 6: 4, for example, in the case of 9: 1, the crack resistance is lowered. In addition, a high purity epoxy resin is required in which the equivalent of each epoxy resin constituting the epoxy resin mixture is 190 to 250 and 120 to 180.

In the present invention, the epoxy resin mixture is used 3.5 to 9.0% by weight based on the total composition.

The curing agent used in the present invention may be used a conventional phenol novolak resin, cresol novolak resin, Xylok resin, dicyclopentadiene resin and the like having two or more hydroxyl groups having a hydroxyl equivalent of 100 to 200, Although these may be used alone or in combination of two or more, it is preferable to use at least 50% by weight of the entire phenolic novolak-type resin from the viewpoint of economy and moldability. It is preferable that the epoxy equivalent of an epoxy resin and a hardening | curing agent is 0.8-1.2 with respect to the hydroxyl equivalent, and the usage-amount of hardening | curing agent is used 2.0-6.5 weight% with respect to the whole composition.

The curing accelerator used in the present invention is a component necessary for promoting the curing reaction of the epoxy and the curing agent, for example benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, tri (dimethylaminomethyl) phenol, and the like. Imidazoles such as tertiary amines, 2-methylimidazole and 2-phenylimidazole, organic phosphines such as triphenylphosphine, diphenylphosphine and phenylphosphine, tetraphenylphosphonium tetraphenylborate And tetraphenylboron salts such as triphenylphosphine tetraphenylborate and the like, and may be used alone or in combination of two or more thereof, and the amount of use thereof is 0.1 to 0.3% by weight based on the total epoxy resin composition.

As the modified silicone oil used in the present invention, a silicone polymer having excellent heat resistance is preferable, and a silicone oil having an epoxy functional group, a silicone oil having an amine functional group, a silicone oil having a carboxyl functional group, and the like are mixed in one kind or two or more kinds. 0.5 to 1.5% by weight may be used based on the epoxy resin composition. However, when the silicone oil is used in excess of 1.5% by weight, surface contamination is likely to occur, and the resin bleed may be long, and when used in less than 0.5% by weight, sufficient low modulus of elasticity may not be obtained.

Inorganic fillers used in the present invention preferably use molten or synthetic silica having an average particle of 0.1 to 35.0 µm, and the filling amount should be 82% by weight or more based on the total composition. When the inorganic filler is used in an amount of less than 82% by weight, sufficient strength and low thermal expansion cannot be realized, and moisture permeation becomes easy, and it becomes fatal to reliability characteristics. However, the upper limit of the amount of inorganic charge is preferably selected in consideration of moldability, it is preferable to use less than 89% by weight. In addition, it is preferable to use a mixture of pulverized and spherical silica having a composition ratio of 7: 3 to 0:10 as a high purity product.

In addition, the molding materials of the present invention include flame retardants of bromo epoxy, flame retardants such as antimony trioxide, aluminum hydroxide, antimony pentoxide, release agents such as higher fatty acids, higher fatty acid metal salts, ester waxes, carbon black, organic and inorganic dyes, and the like. Coupling agents, such as a coloring agent, an epoxysilane, an aminosilane, and an alkylsilane, can be used as needed.

As a general method for producing an epoxy resin composition using the raw materials described above, uniformly and sufficiently mixed the above-mentioned compounding amount using a Henschel mixer or a Rodige mixer, melt-kneading with a roll mill or kneader to cool and grind. A method of obtaining the final powder product is used.

As a method of sealing a semiconductor element using the epoxy resin composition obtained in the present invention, a low pressure transfer molding method is most commonly used, but it can also be molded by an injection molding method or a casting method.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-2

In order to prepare the epoxy resin composition for sealing a semiconductor device of the present invention, as shown in Table 1, each component was weighed, and then uniformly mixed using a Henschel mixer to prepare a powdery primary composition. Epoxy resin composition was prepared by melt kneading at 100 ° C. for 7 minutes, followed by cooling and grinding.

The properties and reliability of the epoxy resin composition thus obtained were evaluated, and when molding a TSOP-type semiconductor device for reliability test, a molding was performed at 175 ° C. for 60 seconds using an MPS (Multi Plunger System) molding machine, followed by 6 at 175 ° C. After curing for a time to produce a TSOP-type semiconductor device.

Table 2 shows physical and reliability test results of the epoxy resin composition according to the present invention. Reliability tests were indicated by the degree of package cracking in the thermal shock test.

Property evaluation method

1) Spiral Flow

The mold was manufactured based on the EMMI standard and the flow length was evaluated at a molding temperature of 175 ° C. and a molding pressure of 70 kgf / cm 2.

2) glass transition temperature (Tg)

It was evaluated by TMA (Thermomechanical Analyzer).

3) coefficient of thermal expansion (α)

Evaluation was made by ASTM D696.

4) Flexural Strength and Flexural Modulus

It was evaluated by ASTM D190 using a universal test machine (UTM).

5) Crack resistance evaluation (reliability test)

After Precondition After 1,000 cycles in the Thermal Shock Environmental Tester, a nondestructive tester, SAT (Scanning Acoustic Tomograph), evaluated the occurrence of cracks, and the preconditioning condition and thermal shock test were as follows.

① Precondition

TSOP-type semiconductor device made of epoxy resin composition was dried for 24 hours at 125 ° C, then subjected to 20 cycles of thermal shock test, and then left for 168 hours under 85 ° C and 65% relative humidity conditions, and then IR ripple for 10 seconds at 235 ° C. Pass the rows three times to evaluate package cracks under preconditions first. If cracks occur at this stage, the next stage, the 1,000 cycle thermal shock test, is not conducted.

② Thermal Shock Test

After 1,000 cycles, the semiconductor package that passed the preconditions was left for 10 minutes at -65 ° C, 5 minutes at 25 ° C, and 10 minutes at 150 ° C for 1 cycle. Evaluate external cracks.

Comparative Examples 1 and 2

As shown in Table 1, each component was weighed out according to a given composition to prepare an epoxy resin composition in the same manner as in Example, and the results of evaluation of physical properties and reliability are shown in Table 2. Units are expressed in weight percent.

Ingredient Example 1 Example 2 Comparative Example 1 Comparative Example 2 Epoxy resin Formula 1 3.0 1.0 5.58 - Formula 2 3.0 3.99 0.62 4.9 Brominated epoxy resins 2.15 1.79 2.23 1.76 Antimony trioxide 2.0 1.0 2.0 1.0 Phenolic Novolac Resin 5.06 4.53 4.77 4.64 Triphenylphosphine 0.16 0.14 0.17 0.13 Silica 83 86 83 86 γ-glycithoxypropyltrimethoxysilane 0.66 0.69 0.66 0.69 Epoxy modified silicone oil 0.41 0.34 0.42 0.33 Carbon black 0.25 0.25 0.25 0.25 Carnauba Wax 0.3 0.3 0.3 0.3

Evaluation item Example 1 Example 2 Comparative Example 1 Comparative Example 2 Spiral Flow (inch) 31 28 29 35 Glass transition temperature (Tg) (℃) 145 120 156 115 Thermal expansion coefficient α (㎛ / m ℃) 10.2 8.5 11.0 8.7 Flexural Strength (kgf / ㎡) 16 18 15 17 Flexural modulus (kgf / mm2) 2100 2500 2200 2450 responsibility Crack Resistance Evaluation (Thermal Shock Test) Number of Crack-Generated Semiconductor Devices / Total Test Semiconductor Devices 0/64 0/64 5/64 0/64 Formability Void Count (Visual Inspection) 0/640 0/640 0/640 8/640

As shown in Table 2, it can be seen that the resin composition according to the present invention exhibits excellent characteristics in terms of reliability and moldability as compared with the comparative examples.

The epoxy resin according to the present invention has excellent curing properties by using a mixture of a low viscosity epoxy resin having a naphthalene structure and an ortho cresol novolac epoxy resin, and has a high filling inorganic filler to reduce moisture absorption and thermal expansion coefficient, The epoxy resin composition for molding a semiconductor device excellent in molding characteristics and reliability can be obtained by improving the mechanical strength and suppressing the generation of voids generated during molding of the semiconductor device.

Claims (5)

In the epoxy resin composition comprising an epoxy resin, a curing agent, a curing accelerator, a modified silicone oil and an inorganic filler as essential components, the epoxy resin is an ortho novolak-based epoxy resin represented by the following formula (1) and naphthalene represented by the formula (2). An epoxy resin composition for semiconductor element sealing, comprising 3.5 to 9.0% by weight based on the total composition of a bifunctional epoxy resin having a system structure in a weight ratio of 2: 8 to 6: 4. Formula 1

Formula 2

The epoxy resin composition for sealing a semiconductor device according to claim 1, wherein the inorganic filler is contained in an amount of 82 wt% or more based on the total composition. According to claim 1, wherein the curing agent has at least one hydroxyl group having a hydroxyl equivalent of 100 to 200 phenol novolak resin, cresol novolak resin, Xylok resin, dicyclopentadiene resin 1 from the group consisting of Epoxy resin composition for semiconductor element sealing, characterized in that at least two species are selected and used is 2.0 to 6.5% by weight based on the total composition. The method of claim 1, wherein the curing accelerator benzyl dimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, tri (dimethylaminomethyl) phenol, 2-methylimidazole, 2-phenylimidazole, triphenyl phosph At least one selected from the group consisting of pin, diphenylphosphine, phenylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphinetetraphenylborate, and 0.1 to 0.3% by weight of the total epoxy resin composition Epoxy resin composition for semiconductor element sealing characterized by the above-mentioned. According to claim 1, wherein the modified silicone oil is at least one selected from the group consisting of a silicone oil having an epoxy functional group, a silicone oil having an amine functional group and a silicone oil having a carboxyl functional group, 0.5 to the total epoxy resin composition To 1.5% by weight of the epoxy resin composition for sealing semiconductor elements.